Dynamic Optimization Of Structure Based On Genetic Algorithm

Structure at work was affected by vibration and impact loads inescapability. So, dynamic damage and destroy is the primary failure mode of structure. Dynamic optimum design of structure is an effective method to improve the dynamic capability and ensure it working safety and reliably. Support position optimization can optimize most design objects of structure. And, it is familiar method to improve the dynamic character and letdown the dynamic response.On the basis of analyzing and summarizing the fundamental theory and research achievement of genetic algorithm, this paper proposed a new method of dynamic optimization of structure based on genetic algorithm. A new generalized genetic algorithm was presented in this paper and the corresponding program was designed. Many new theories such as integer code, real code, population isolation, optimum reserved strategy and adaptive random mutation were used.Finally, the generalized genetic algorithm and finite element method were used to support position optimization of structure dynamic characteristics and dynamic response. In this method, structure analysis was connected with genetic algorithm program by PCL (Patran command language). Numerical examples demonstrate the validity and effectiveness of this method.To improve the convergence efficiency of the generalized genetic algorithm and avoid inbreeding and premature, this paper proposed heterogeneity strategy firstly. Further more, an expression to estimate the extent of inbreeding and two methods of selecting heterogeneity were given. Heterogeneity strategy means select seeds out of the present searching region with a little probability in the course of genetic optimization and, enter these seeds into the course to increase the variety of the population. It simulated the artificial intervention course of evolution to obtain the optimized species. The working probability of heterogeneity strategy and the region of selecting heterogeneity lied on the present circulation times and the extent of inbreeding.The optimization course shows that, genetic algorithm, as a new random search method based on evolution conception, its mechanics model was not depend on the boundary conditions or load. Consequently, the dynamic optimization method of structure based on genetic algorithm has extensive applicability in complicated structure optimization problem.